The Prognostic Significance of Neuroendocrine Differentiation in Colorectal Carcinomas: Our Experience

Abstract

Introduction: Neuroendocrine differentiation in colorectal carcinomas, detected using immunohistochemistry and ultrastructural techniques, has been studied as a prognostic marker for invention of targeted therapy. There are a few studies done on this aspect which have shown conflicting results ranging from poor prognosis to no prognostic significance.

Aim: The aim of the study was to determine the clinical significance of neuroendocrine differentiation in colorectal carcinomas using immunohistochemical stains such as chromogranin A & synaptophysin in relation to its prognostic significance.

Materials and methods: A retrospective study was conducted wherein all the colorectal carcinomas, received in the Department of Pathology, over a period of 3 years, were reviewed. Neuroendocrine markers were done on 53 cases of moderately, poorly and undifferentiated adenocarcinomas. Based on the degree of immunoreactivity for these markers, tumours were divided into group 0, group 1, group 2, group 3 & group 4. Group 0 & 1 were categorized as neuroendocrine differentiation absent & group 2, 3 & 4 as present. Neuroendocrine differentiation was correlated with age, sex, grade, stage, diagnosis & survival. Follow up data of the cases was recorded.

Results: Neuroendocrine differentiation was present in 18 cases (33.9%). The degree of immunoreactivity for neuroendocrine markers in present study were; group 0- 58%, 1- 7.5%, 2- 9%, 3- 13% & 4- 11%. The mean age of patients was 54 years with a slight male preponderance {M:F::1.6:1}. Most of the carcinomas with neuroendocrine differentiation belonged to Grade II (61%) & Stage II & III (83%). Neuroendocrine differentiation did not show any significant association with age, sex, location, histological type, grade, stage & survival.

Conclusion: The above results indicate that the presence of neuroendocrine differentiation cannot be recommended as a prognostic marker in colorectal carcinomas.

Keywords: Carcinoma of colon; Chromogranin; Prognostic marker; Synaptophysin.

[Table/Fig-2a-f]:

Intensity of Chromogranin A staining (Chg A) a) MD CRC showing Chg A positivity in >30% of the tumour tissue [Chg A Immunoperoxidase, 40x]; b) Mucinous CRC showing Chg A positivity in 10-30% of the tumour tissue [Chg A Immunoperoxidase,100x] Inset: High power view of one of the tumour nests [Chg A Immunoperoxidase, 400x]; c) MD CRC showing Chg A positivity in >2% of the tumour tissue [Chg A Immunoperoxidase,40x]; d) SR CRC showing Chg A positivity in 2-10% of tumour tissue [Chg A Immunoperoxidase,100x]; e) PD CRC showing Chg A positivity in <2% of the tumour tissue [Chg Immunoperoxidase,40x]; f) High power view showing granular cytoplasmic positivity for Chg A [Chg A Immunoperoxidase, 400x]

[Table/Fig-3a-f]:

Intensity of Synaptophysin staining (Syn) a) MD CRC showing Syn positivity in >30% of the tumour tissue [Syn Immunoperoxidase,100x]; b) MD CRC showing Syn positivity in 10-30% of the tumour tissue [Syn Immunoperoxidase, 400x]; c) PD CRC showing Syn positivity in 2-100% of the tumour tissue [Syn Immunoperoxidase,400x]; d) Mucinous carcinoma showing Syn positivity in 10-30% of the tumour tissue [Syn Immunoperoxidase, 40x]; e) High power view showing granular cytoplasmic positivity for Syn [Syn Immunoperoxidase, 400x]; f) SR CRC showing granular cytoplasmic positivity [Syn Immunoperoxidase, 400x]